Vapors, Odors, and Toxic Gases from Landfills

Landfill gas from eight different sites in the United Kingdom was analyzed for trace constituents. Municipal, industrial, and liquid codisposal sites were included. A hazard assessment was made on the basis of the concentrations of potentially toxic components, and some of the causes of landfill odors were identified.

Three trapping methods were used to provide samples for analysis by gas chromatography/mass spectrometry. Supplementary techniques were employed to quantify the bulk gases, hydrogen sulfide, and metallic elements present.

Over 100 organic constituents were identified, but only 10 exceeded their individual recommended toxicity threshold limit values. Toxic compounds were more abundant at industrial sites. Odors were strongest from recently deposited waste, with methanethiol exceeding the odor threshold by a factor of more than 10⁶. Hydrogen sulfide was not a significant cause of odor. Odors from the compounds identified and quantified depend more on the stage of decomposition than on the nature of the waste, and industreal wastes did not exacerbate the smell.